Top 5 Freshwater Sharks for Aquariums (and How Big They Really Get)
You may have gone to the pet store and seen some freshwater fish labeled as “sharks.” These species are not true sharks but rather are members of the Cyprinidae family of carp and minnows. They just happen to look like sharks because of their slender, torpedo-shaped bodies and pointy fins. Freshwater sharks are popular among beginners due to their beautiful shape and hardiness. However, they can get much larger than expected and will require large tanks. Before you buy that cute 5-inch (5 cm) shark from the pet shop, let’s find out about their needs and decide if they are right fish for you.
1. Red Tail Shark
The red-tailed red sharkminnow is also known as the red tail sharkminnow. This species can be easily identified by its completely black body, fins and bright red tail. As a juvenile, they can be quite sweet and tiny. However, an adult red-tailed shark can grow to approximately 5-6 inches (13-15cm) in length and requires an aquarium of at least 4ft (1.2m) in length. They come from Thailand’s rivers, streams, and floodplains during the rainy season, which means they are accustomed to living in a wide range of pH between 6-8 and temperatures from 72-79degF (22-26degC). They are omnivores and will eat anything, including fish flakes, sinking wafers, and certain types of algae, just like all the sharks in this list.
Red tailed sharks are solitary creatures and not schooling fish, so as they grow older, they become very territorial towards members of their own species and other sharks. They are able to live with other semi-aggressive fish of similar size, such as African cichlids and South and Central American Cichlids. You can also pair them with slightly smaller, super-fast schooling fish, like giant danios and barbs. Avoid peaceful fish, slow swimmers or nano creatures that could be eaten as tank mates.
2. Rainbow Shark
This magnificent centerpiece fish can grow to 5-6 inches (11.3-15 cm) in length and is very similar to the red-tail shark. They are not nearly all black but have a darker gray coloration and red tail. Plus, pet stores commonly sell different color variations, such as the albino and Glofish versions. They also come from Thailand and nearby Southeast Asian countries and can live in a broad gamut of pH levels between 6.5-8.0 and temperature from 72-80degF (22-27degC). They enjoy eating all kinds of community fish foods like pellets, wafers, blanched veggies, and frozen foods. When they feel hungry, they will often eat alga when available.
Rainbow sharks can be more social than juveniles but they become more aggressive towards other species as they age. Limit the number of rainbow sharks you keep to one per 4ft (1.2m) aquarium length. You can find suitable roommates in rainbowfish, loaches and gouramis as well as cichlids, loaches and gouramis that are similar in size. However, it is possible to remove tank mates from your tank if you are not happy with the arrangement or if the rainbow shark bullies them.
3. Roseline Shark
Roseline sharks are named for the red horizontal stripe that runs down its middle. It is a shorter, more prominent line of color than the longer, blacker lines. They are also known as Denison barbs and can grow up to 4-5 inches (10-13cm) in length. Their tails have beautiful yellow and black markings. They come from fast-moving rivers and pools in India with dense vegetation near the banks and would appreciate living in a planted aquarium. They are a schooling fish that requires 3-5 people to keep them happy. A tank should be at least 4 feet in length (1.2 m) and larger. They are a peaceful and smaller fish that would be great with rainbowfish and larger livebearers. They will be happy to eat a variety of frozen, prepared, freeze-dried, gel and other foods.
4. Siamese Algae eater
Do you need an algae eater to cover larger tanks? The Siamese alga eater (SAE), 6-inches (15 cm) has a silvery-brown body and a bold black line running down its side. This fish will eat both black beard algae and leftover fish food. They tend to eat more algae as juveniles because the adults are large enough to get the lion’s share of the fish food you feed. To encourage the adults to go after algae, you may need to fast them for about a week to get them hungry enough.
They are native to rivers and floodplains of Southeast Asia. They can live in pH 6-8 and tropical temperatures between 72-79degF (22-25 degC). While you can get a school of them if you need lots of algae-eating power for a large aquarium, they tend to become territorial with age towards other sharks, including their own species. You could keep one of them in a 50-gallon aquarium or larger. They will be content living alone.
5. Bala Shark
The longest shark on our list is 12 inches (30cm) in length. It is also known as the tricolor shark or silver shark. It has a silvery body with light-colored fins and thick, black edges. They are able to survive in a pH range of 6-8 and temperatures between 72-82degF (22-24 degC) as they live near rivers and lakes in Southeast Asia. They are quite easy to feed and will readily eat any floating or sinking foods, as well as invertebrates like shrimp and snails.
This species is not recommended for aquarists due to its huge tank size requirements. You need to allow them plenty of space. It is difficult to find an aquarium that has at least six feet (1.8m) of length for this giant fish. Many hobbyists end-up only getting one bala shark for their 125-150-gallon fish tank. They can be kept together with similar-sized, semiaggressive fish such as cichlids and catfish.
If you are serious about caring for a freshwater fish shark, and making sure that it has the right size tank and tank mates to thrive, then we suggest checking out our preferred online retailers. All the best with your aquariums. Enjoy nature every day.